Update: I was unfortunately not aware of Shamus Young's severe criticism of Fallout 3 available here to link in the original piece and I regret that. It dovetails rather nicely with what I've written and it's much better executed than my piece. I strongly recommend anyone...

Kingdoms of Amalur: Reckoning Cheats for the Xbox360

End Reckoning Mode with the most difficult enemy
How much bonus experience you earn from Reckoning Mode depends slightly on the length of the kill animation. The longer the animation, the more time you have to button-mash the corresponding button. Choosing the largest, most difficult enemy (particularly trolls and Jottun warriors) usually results in a longer kill animation.

Save lockpicks by pulling back
Many times, you can tell if a lockpick is going to break by the speed of the spring as it goes across the top of the screen. A lockpick in the perfect position will let the spring go at a fast pace; keep that speed in mind. Any slower than that and the lockpick is bound to break; letting go of the spring will save the lockpick.

Save before dispelling chests and persuasion checks
Use the save system to your advantage. Failing to dispel a chest can result in a nasty curse, so saving before then and reloading if you fail is a good way to save time. The same goes for persuasion checks, which are percentage-based. If you think you'll be going into a conversation with a persuation check, save beforehand.

Attack enemies from beyond their spawn point
Especially in dungeons, some enemies can't venture past a certain distance away from their original spawn point. So if you pull an enemy far enough, it will stop chasing you and run back without regenerating its health. This trick can be used to kill an enemy that's giving you too much trouble or to thin out a crowd of difficult enemies.

Achievements

Teeth of Naros Achievements

Beam Me Up (25) - Used the Henge to enter Idylla.
I Regret Nothing (5) - Fell to your death from the Idylla Concourse.
Mistaken Identity (25) - You've found a strange Almain who has been hiding in the sewers of Idylla.
Murder Most Fowl (25) - Kill 50 Pteryx.
The Harder They Fall (20) - You've bested Kahrunk without killing his attendants.
We Built this City (50) - You helped the Kollossae in the Teeth of Naros break free from their fate.